This invention relates to campstoves, and, more particularly, to improved burner assemblies for campstoves.
Campstoves which use liquid fuel typically include a burner assembly in which a burner box for mixing fuel and air is located below the burner. A generator tube delivers vaporized fuel to the burner, and a fuel and air mixture flows upwardly from the burner box to the burner where it is ignited. U.S. Pat. No. 4,126,117 (reissued as U.S. Pat. Re. No. 31,738) describes this type of campstove.
U.S. Pat. No. 3,933,146 describes a campstove which uses propane fuel. This campstove also includes a burner box which is positioned below the burner.
In conventional liquid fuel burner assemblies in which the burner box is positioned below the burner, any fuel which is ejected from the generator tube in a liquid state collects in the bottom of the burner box away from the burner. The possibility of liquid fuel collecting in the burner box is even greater in cold temperatures. A substantial period of time can elapse before this liquid fuel is vaporized and reaches the burner, and the efficiency of the burner assembly is thereby reduced.
Flooding of the burner box with liquid fuel also interferes with the start-up of the burner assembly. Campstoves are commonly provided with an instant-light fuel supply mechanism which supplies a fuel-air mixture to the generator tube so that the burner can be ignited before the generator tube is heated sufficiently to vaporize the fuel in the generator tube. After the burner is ignited and heats the generator tube sufficiently to vaporize the fuel in the generator tube, the instant-light mechanism is turned off and only fuel flows through the generator tube. Liquid fuel which collects in the burner box during start-up is not available for combustion at the burner, and more time is required to heat the generator before the instant-light mechanism can be turned off. Since the burner burns less efficiently during start-up and emits less heat, a short start-up time is desirable.
Conventional burner assemblies also include means for mixing fuel and air and delivering the fuel-air mixture to the burner for combustion. It is important that the fuel and air are mixed thoroughly before ignition to provide a properly carbureted fuel mix for optimum efficiency, i.e., the smallest amount of fuel for a given BTU output.